Questions tagged [tv]

Use this tag for technical aspects of TV (video formats, for example). Shopping questions are off-topic and repair questions might be too localized.

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14
votes
2answers
2k views

Generating PAL tv signal using a PIC

I'm trying to generate PAL tv signals using a PIC24FJ64GB002 using a similar method to the circuit described half way down this page. The only difference is that my circuit needs to run at 3v instead ...
8
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2answers
1k views

Circuitry of TV splitters

I'm trying to understand the circuitry of TV signal splitters and associated boosters/amplifiers, and I have two questions. My situation is as follows. I have a TV aerial (antenna) in my loft. It ...
8
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4answers
1k views

TV screen in still photo: Why are there dark, blackish bands?

I was trying to capture the scanning process of a CRT TV screen in a photo. It gave me these dark, broad bands, shown below: Fig. 1 a,b,c I'm trying to understand the cause for this banding. However,...
6
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1answer
9k views

What is the function of “Picture tube charger”?

There is a bizzare device called picture tube charger or CRT-Charger. Here I attach the some diagrams of it from a circuit-book. Now, what is its function? what changes it create inside the CRT? ...
6
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2answers
641 views

Why the audio subcarrier is never transmitted with baseband analogue video signal?

In the era of analogue video, when you needed to connect a local video source (STB, VCR, game console, DVD player, etc.), the most ubiquitous way to do so, next to using an RF modulator, would be to ...
5
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2answers
2k views

White Dust: Is it bad for electronic devices like smart TVs or phones?

As a side result of using an ultrasonic air humidifier, this white dust thing can be seen on house furniture during its activity. I googled about it but I only found a few articles, saying that it is ...
5
votes
1answer
4k views

Why is an HDMI signal causing interference with Over-The-Air digital television? [closed]

I do not have cable or satellite television so I rely on Over-The-Air digital programming (free) and Internet streaming services to provide entertainment. A couple years ago, I purchased a video card ...
5
votes
2answers
74k views

Is it possible to combine independent digital TV antennas?

Is it possible to create a TV antenna that is composed of smaller antennas that are pointed to different broadcast centers? So in essence, many antennas for just a single digital TV. Is it possible ...
5
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1answer
136 views

How do LCD screens repair themselves?

Hey, electronics people: A few months ago, I cleaned a spot on an LCD flat screen. Whatever it was, it was stuck on there pretty good and I guess I pushed down on it too hard (actually wasn't hard at ...
5
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2answers
1k views

Is my LCD TV doing some sort of dithering? [closed]

I'm using a 32" 'LED' TV as a monitor (1920x1080 over HDMI). I've been noticing some annoying horizontal stripes where the source is displaying grey pixels. It seems that what's happening is the TV ...
4
votes
1answer
2k views

Color problems when turning a CRT TV set into an oscilloscope

I found an old CRT TV set in the garbage. It didn't work, always showing the "snow effect", even when I connected it to another device via the SCART port. So I followed an online tutorial to make it ...
4
votes
2answers
576 views

What makes “quality” analog AV cables better than cheap cables? [closed]

I want to upgrade my retro game setup from a mix of composite and RF to a mix of S-video and component, with some composite for the really old stuff that doesn't support S-video. How can I distinguish ...
4
votes
1answer
340 views

How do receivers know what to output to radio speaker or TV screen?

I understand that receivers are often used with mixers which take the sum and difference of two signals to make an output signal. How does a radio signal of say 102.5 MHz know to tell the speakers to ...
4
votes
1answer
1k views

Can a small gauge wire be used in a fractal antenna?

I want to make a fractal antenna to replace an old set of rabbit ears. All the guides I've seen have used a thicker wire (metal coat hangers seem popular). While I don't have any hangers, I do have an ...
4
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1answer
1k views

What is this component and what is its use?

I found this in CRT TV on the CRT tube driver PCB. What are they and what is their schematic symbol?
4
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1answer
140 views

What level of a square wave signal should be safe for TV receivers?

I am experimenting a bit with TDR (time domain reflectometry) and for it I am generating a square wave with up to 10kHz and a rise time of about 1-2ns. Now I would like to put that thing to use and ...
4
votes
1answer
182 views

How do we know off-screen area in TV?

I'm trying to implement HDMI to FPGA and vice-versa. Currently I'm referring with https://www.fpga4fun.com/HDMI.html site. But I'm confused that "But video signals usually also have an "off-screen" ...
3
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8answers
16k views

Why there is 625 lines [ PAL ] in T.V. scanning or odd lines?

I can't get why there are 625 lines in a PAL scanning system. I read R.R.Gulatti's standard book. In that there is a reason like: "Suppose there are x lines in 1 field. Then for two field its 2x....
3
votes
1answer
1k views

What is the function of this cable surrounding the CRT of old televisions

I have opened old televisions, and each time, I'm wondering what is the function of this cable, roughly insulated with some tape. Note: I know what are the risks of opening televisions.
3
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2answers
14k views

Philips/Magnavox LCD TV Service UART / ComPair

I have a Magnavox 42MF438B/27 42" LCD TV. The IR sensor (or something related) quit working after awhile, so we have been unable to use the remote. Today, I was digging around behind the TV and ...
3
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3answers
278 views

DIY Single-Channel Television

My building recently installed a CCTV camera system. Anyone with cable TV is able to tune into channel XX and watch the CCTV stream live. I want to get a cheap and small LCD (≤7") and build a ...
3
votes
2answers
287 views

What are some economical ways to get a remote analog video feed?

I am a computer programmer and I like playing with robots. But I don't have access to tons of cool toys so I try to make do with what I've got. The other day I was trying to navigate an R/C car ...
3
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0answers
2k views

CRT TV NOT TURNING ON [closed]

I'm a beginner in electronics repairing and I need help troubleshooting a tv which doesn't turt on, neither the power LED lights up. The board is a cheap chinese (check the attached image). When I ...
2
votes
2answers
2k views

Split TV signal to make a video wall

I'm working on this project for University. We are generating visuals by sending audio signals from the computer to an old tv. Left channel to TV's Vertical, right channel to TV's horizontal. We send ...
2
votes
1answer
545 views

127v 60hz TV to 220v 50hz [closed]

Hi all I recently moved from Mexico to Portugal and brought some electronics I suspect they are multi voltage and multi frequency. But reading the label of a Sony TV I got into doubt if it is or not ...
2
votes
1answer
917 views

How can PAL (TV) encode 3 colors in 1 phase?

As I understand it luminance is the amplitude of the signal, and color is the phase. You need 2 color signals (the third one can be derived from the other 2, like B = 1 - R - G). How can 1 phase ...
2
votes
1answer
2k views

are there 2 basic-type of CRT deflection-yoke coil?

Deflection coil inside TV, deflects the electron-beam, using magnetic field. However this-deflection is not as simple as electrostatic deflection. What is the actual mechanism behind working of ...
2
votes
2answers
184 views

Detecting TVs with PC's graphics card

I'm interesting of how can graphics cards detecting what type of TV has connected with S-Video? TVs sent some indefiniter signal back to the computer? And how it's working (protocols, signals, freq, ...
2
votes
1answer
7k views

V-control broken on old (CRT) TV-Set?

I found a TV-Set in a dumpster, and checked if it's still working. Indeed it is somewhat functional, but the picture is distorted: (screenshot of the TV) Depending how bright the picture is, it get'...
2
votes
1answer
96 views

Identifying SMD component 22P W8

I've been trying to identify a component on a main board for a TV that I believe to be faulty. As I haven't been able to come up with anything that I feel confident about, I'm hoping to get some ...
2
votes
1answer
79 views

TV display shimmering [closed]

First, a video: longer, higher quality This is a closeup of my TV, of a still picture (the Xbox One menu) There is no motion, the TV has all filtering, sharpening, etc disabled. Could it be that ...
2
votes
1answer
602 views

Do LCD's or Plasmas have a circuit for each pixel or they are lit in an array fashion?

I'm trying to understand how LCD's display a picture. I've read articles and papers, but sometimes I get contradicting information. Some say that each pixel ( actually a sub-pixel ) have their own ...
1
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2answers
4k views

TV signal into an Oscilloscope

I'm plugging TV signal cable directly into an oscilloscope. TV cable looks like this: First I connected outer shell of TV cable connector to GND of oscilloscope BNC cable and center to the center of ...
1
vote
2answers
4k views

What is the difference between a tuner and an antenna?

I was just told by my TV's customer service that my TV had a tuner but no Antenna as a response to my question - Can I use my TV's inbuilt Antenna to pick up over the air channels? I was wondering if ...
1
vote
1answer
601 views

Will a 1950s television still work? [closed]

My company has a Philco Predicta television model H3407 as described here: Philco Predicta description. Will this TV still work with modern broadcasts?
1
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2answers
176 views

Horizontal overscan on NTSC

How much horizontal overscan is there on a typical NTSC CRT television set? Vertical overscan, there are nominally 240 scan lines per field, of which you can reasonably count on having slightly more ...
1
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2answers
1k views

How do I operate a tuner of digital satellite receiver using a microcontroller?

I want to operate this tuner of my digital satellite receiver. This is the tuner: They wrote some numbers and words around of the tuner: and the name and model of the receiver is "DigiStar D600 ...
1
vote
2answers
695 views

Testing a video transmitter for video bandwidth

I need to test the bandwidth of a variety of video transmitters to figure out the maximum resolution I can safely output without losing detail. To this end, I came up with a solution using a TV ...
1
vote
1answer
700 views

How dangerous are portable CRT televisions?

I want to use an old portable CRT for a project, but I don't know how dangerous the capacitors are, and if they'd be as bad as the ones inside a normal CRT. It takes in 12v dc via adapter, or 8 D ...
1
vote
1answer
1k views

Streaming UHF/VHF/AM/FM over IP

I am working on a project that can stream TV and Radio signals over IP. I found a device to capture the signals and send them over IP realtek-rtl2832u but I am ...
1
vote
3answers
235 views

Two TVs use the same antenna, but one affects the other

I’m having a problem with my TVs. I will call them TV1 and TV2. TV1 is Asanzo brand, and TV2 is LG 4K, which is much more expensive. After replacing the antenna wall socket of TV2 (The TV is near to ...
1
vote
1answer
86 views

Can I connect TV Speakers to an interface and use them as stand alone? [closed]

A couple of months ago I broke my TV and the only thing I could kept were the internal TV speakers The TV was an LG 55EA9800. Now, my laptop has been giving me issues with the sound, I think the ...
1
vote
1answer
464 views

Why is the refresh rate of most LED LCD TVs 60Hz?

Can anyone explain to me why (at present day) the refresh rate of most LED LCD TVs is 60Hz? Is there a physical limitation to the technology of LED TVs that make it much more expensive to implement a ...
1
vote
1answer
81 views

Television Radio Module or Circuit

I want to listen TV channels without display (terrestrial) just like FM Radio channels. There are lots of FM receiver circuits on the web but I couldn't find for TV channels. Is such a thing possbile ...
1
vote
2answers
3k views

What is the purpose of the diodes on a Samsung LED TV backlight bar

Skip to the question below if you don't care about the details ;) The bottom half of the backlight in my TV went off so I opened it up to see if I could fix it. I found four of the 7 bars of LEDs ...
1
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1answer
395 views

Why cable TV frequency range ends at 1 GHz?

Currently frequencies 50-1000 MHz are allocated for TV and data transfers. I understand why there are limitations for aerial or satellite transmissions, but why are they retained for cable ...
1
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2answers
97 views

Project - How to onstruct a circuit to introduce and control a 0-300ms delay in an RF feed from a Sky Box to multiple TV sets? [closed]

Just bought a new TV! It's "smart" but where my previous dumb TV didn't, my smart TV introduces a delay over HDMI from my Sky+HD box compared to the RF2 output which is wired via coax cable to the ...
1
vote
1answer
576 views

Philips 26PF5321 backlight mod, dim backlight

Got this older Philips 26PF5321 LCD-TV, like it because it is not a smart-tv. What I dislike about this TV is the fixed backlight setting (cannot change it via software menu and there is no update ...
1
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0answers
74 views

How could I interpret these-2 YUV modulated picture given in wikipedia? is it correct simulation? or something I'm missing?

While reading the wikipedia article on YUV color modulation (which is used in PAL color tv receivers); I visited this diagram: (Wikimedia); (and according to the image description there; i.e. "...
1
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0answers
551 views

Does the rt2832u chip have enough bandwidth for ATSC?

I'd like to upgrade the audio/infotainment module in my 2009 Camry. I see several off the shelf solutions, but they don't have a builtin digital TV tuner and the processor isn't as fast as I'd like. ...